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Novel method of improving squirrel cage induction motor performance by using mixed conductivity fabricated rotors (MCFR) / Constantin Danut PitisPitis, Constantin Danut January 2006 (has links)
The ideal squirrel cage motor should have a varying rotor resistance; large at standstill, and decreasing as the speed rises. Overseas - designed high impedance rotors try to fulfil these conditions - mostly used are double cage rotors and die cast aluminium rotors. However, in the South African coal-mining industry these rotors recorded high rate failures with heavy financial losses. As a result, the need for an alternative rotor type that was able to comply with basic conditions ignored before appeared on the market: • Higher reliability with extended life expectancy • Lower total ownership costs • Easy re-manufacturing with components available on the market • Specific performance stability at competitive price. Over the years, only two principles were tacitly accepted in designing squirrel cage rotors: 1. For a single cage rotor, in a circumferential direction around the rotor the squirrel cage bars are placed in the same cylindrical shell, with the same shape and same conductivity. 2. For a double cage rotor, the same rule as above applies; however, in the radial direction, the bars have different shapes and typically different conductivities.
The Invention is based on a new principle, i.e. "in a circumferential direction around the squirrel cage rotor, squirrel cage bars may have different conductivities and same shapes, or different conductivities and different shapes”.
Mixed Conductivity Fabricated Rotors (MCFR) are designed and manufactured based on this
new principle, and are able to withstand the harsh South African mining conditions.
Since patented, the invention has been materialised in a set of special rotors powering
continuous miners of a reputable coal-mining house, which was spending about R5 million
annually on replacing specific imported die cast aluminium rotors only.
Fully complying with the above-mentioned basic conditions, the patent offers a large variety of technical and economical advantages, increasing mining processes efficiency beyond
expectations.
The thesis describes the MCFR's design adaptability by altering the rotor design to meet the demands of a specific engineering application as a base line of drives design.
The patent is part of the new South African trend of increasing processes efficiency. It offers large possibilities of designing dedicated motors with a positive impact on the South African economy. Some socio-economical advantages are worthy of considerable study: • Being locally manufactured, the MCFR may reduce the country's economical dependence. • Requiring no special expertise, the MCFR can be produced in any quantity and size without excessive investment. • The MCFR offers an alternative option (product interchangeability) on the market as well as sound competition (with export potential). • The patent ensures business sustainability conditions which diffuse financial constraints on motor manufacturers and end-users during the re-capitalisation process (very loaded in South African economic and industrial environment). / Thesis (Ph.D. (Electrical Engineering))--North-West University, Potchefstroom Campus, 2007.
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Quantifying guidelines and criteria for using turbulence models in complex flowsAbdullah, Aslam January 2011 (has links)
A framework for assessing the key statistical parameters of complex flows in choosing appropriate turbulence prediction methods on a quantitative basis is developed. These parameters characterise flow/modelling matching conditions quantified in this work. Matching conditions are important in classifying complex turbulent flows in order to frame best practice for model predictions to inform computational aerodynamics design optimisation in the context of virtual test beds. In the incompressible low Reynolds number shear flows considered here, the boundaries of the 'conforming domain' within which turbulence models are valid need to be defined, based on basic mechanisms of turbulence, and the statistical parameters. This has led to a new guideline ‘localness map’ for standard model applications. Since the choice of turbulence model depends on the complexity of the flows considered, it is useful if systematic sets of the parameters indicate the type of flow. They are that of residence time, the degree of spatial non-locality, the straining, and the non-Gaussianity, each of which is appropriately normalised. It can be demonstrated that the quantified map, in particular that of localness for the shear flows, provides a firm foundation for evaluating a wider range of Underlying Flow Regimes, including locating the Underlying Flow Regimes on the generalised localness modeling map as a framework for best practice guidelines. This work produces 7 sets of quantitative localness-structural parameters, which are used as baseline sets for grouping the Underlying Flow Regimes, and hence it opens the possibility of having complete modelling maps for Application Challenges to assess the need for zonal modelling.
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Solving a highly constrained multi-level container loading problem from practiceOlsson, Jonas January 2017 (has links)
The container loading problem considered in this thesis is to determine placements of a set of packages within one or multiple shipping containers. Smaller packages are consolidated on pallets prior to being loaded in the shipping containers together with larger packages. There are multiple objectives which may be summarized as fitting all the packages while achieving good stability of the cargo as well as the shipping containers themselves. According to recent literature reviews, previous research in the field have to large extent been neglecting issues relevant in practice. Our real-world application was developed for the industrial company Atlas Copco to be used for sea container shipments at their Distribution Center (DC) in Texas, USA. Hence all applicable practical constraints faced by the DC operators had to be treated properly. A high variety in sizes, weights and other attributes such as stackability among packages added complexity to an already challenging combinatorial problem. Inspired by how the DC operators plan and perform loading manually, the batch concept was developed, which refers to grouping of boxes based on their characteristics and solving subproblems in terms of partial load plans. In each batch, an extensive placement heuristic and a load plan evaluation run iteratively, guided by a Genetic Algorithm (GA). In the placement heuristic, potential placements are evaluated using a scoring function considering aspects of the current situation, such as space utilization, horizontal support and heavier boxes closer to the floor. The scoring function is weighted by coefficients corresponding to the chromosomes of an individual in the GA population. Consequently, the fitness value of an individual in the GA population is the rating of a load plan. The loading optimization software has been tested and successfully implemented at the DC in Texas. The software has been proven capable of generating satisfactory load plans within acceptable computation times, which has resulted in reduced uncertainty and labor usage in the loading process. Analysis using real sea container shipments shows that the GA is able to tune the scoring coefficients to suit the particular problem instance being solved.
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Provoking Placebo : A Literature Study About Placebo Response in NursingLärkefjord, Gabriel January 2017 (has links)
Background: The placebo effect and the placebo response is a misunderstood phenomenon and their potential is wildly underestimated. Most people, including health care professionals, consider the placebo effect to be a “make believe” effect which only affects gullible people. It is argued that the nurse is in an unusually advantageous position to observe and facilitate the placebo effect and make use of the benefits for the patients. Observation of said response is made by many authors but there is little to no research on the placebo effect from a nursing standpoint. Some of the research results can however be translated to the nurse profession and used in clinical settings. Aim: The purpose is to describe areas where the placebo effect may affect nursing of the patient. Method: A literature review format was chosen to comprise existing knowledge on the placebo effect, which can be applied for nursing. Results: Themes that arose from examination of chosen literature included: Emotional state, Expectation and Conditioning, Conscious and Social learning and Patient-caregiver relationship. Many of the observed interventions could be applied using the nursing philosophy of Hildegard Peplau. Conclusion: The placebo effect can be used by the nurse to improve the result of the patient´s treatment. If placebo becomes a focus in nursing research the results could be more applicable to benefit patients than if researched by other professional groups.
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Toward A Life-Changing Application Paradigm in Expository PreachingPark, Hyun Shin 23 May 2012 (has links)
The primary aim of this dissertation is to examine the hermeneutical foundation, the biblical basis, the historical principle, and then to formulate a four-bridge application paradigm based on four distinguished processes--exegetical, doctrinal, homiletical, and transformational--aiming at transforming the lives of listeners for the glory of God.
Chapter 1 analyzes the indispensability of a well-balanced hermeneutical application paradigm by arguing the relationship between hermeneutics and application, by reexamining application paradigms and bridge-building models, and by refocusing the four bridge paradigm.
Chapter 2 examines the sermons of biblical prototypes--Moses, Ezra, the Minor Prophets, and Paul--and their features of application paradigms by means of a paradigmatic analyses rather than an exhaustive one. This chapter thoroughly explores Paul's sermons in his epistles, his preaching in Acts, and his hermeneutical bridge-building paradigm. The essential characteristics of these biblical models lead to a four-bridge life-changing application paradigm.
Chapter 3 investigates four exemplary historical models--John Chrysostom, John Calvin, Jonathan Edwards, and John Broadus--and examines their illustrative sermons to identify their indispensable principles of application paradigms and to apply these historical facets for formulating a contemporized application paradigm. Four models provide a historical validation to formulate a legitimate life-changing application paradigm.
Chapter 4 proposes a four-bridge application paradigm rooted in hermeneutical, biblical prototypes and historical models. The chapter systemizes (1) an exegetical bridge for discerning the aim of author-intended signification and the criteria for transferring universal principles of application (2) a doctrinal bridge for examining seven master keys to unlock the universal principles of ethical application, (3) a homiletical bridge for identifying a variety of relevance categories, legitimate methodologies of audience exegesis and adaptation, and an appropriate degree of transfer, and (4) a Spirit-led transformational bridge that is legitimate to change the lives of listeners.
Chapter 5 concludes that contemporary preachers, as bridge-builders, need to seek a life-transforming application paradigm by utilizing the exegetical bridge, the doctrinal bridge, the homiletical bridge and the Spirit-led transformational bridge.
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Faciliter la mise en place d'études d'utilisabilité par des outils de stockage des données et d'analyse automatique des traces d'utilisation : un cas d'étude avec une application mobileCribier-Delande Perrine January 2016 (has links)
Le laboratoire DOMUS développe des applications pour assister les personnes en perte d'autonomie et les personnes avec des troubles cognitifs. Chaque application est ou a déjà été le sujet de plusieurs études d'utilisabilité qui permettent de les améliorer. Ces études prennent beaucoup de temps à mettre en place, car l'on rencontre souvent des problèmes de logistique (format et sensibilité des données, chercheurs répartis sur une grande aire géographique). C'est pourquoi un outil appelé GEDOPAL a été développé. Il permet de partager entre chercheurs de différents centres les données créées et utilisées lors de la mise en place des études d'utilisabilité. La conception et la réalisation de cet outil ont nécessité une réflexion en amont sur la nature et la sensibilité de ces données. Cette réflexion est l'objet du Chapitre 3. Ces études prennent aussi beaucoup de temps lors de l'analyse des résultats. De plus, certaines données créées lors de ces études, telles que les traces d'utilisation ont des volumétries trop importantes pour être analysées manuellement. C'est pourquoi nous avons créé un processus permettant d'analyser ces traces d'utilisation pour y détecter les erreurs utilisateurs dans l'espoir de les relier à des problèmes d'utilisabilité. Ce processus se compose de deux parties : la première est une analyse formelle de l'application, qui sera présentée au Chapitre 4, et la seconde l'application d'un outil d'apprentissage automatique aux traces d'utilisation pour y détecter les erreurs utilisateurs. Cet outil est présenté au Chapitre 5.
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Job search portalSowmya, Mathukumalli January 1900 (has links)
Master of Science / Department of Computer Science / Mitchell L. Neilsen / Finding jobs that best suits the interests and skill set is quite a challenging task for the job seekers. The difficulties arise from not having proper knowledge on the organization’s objective, their work culture and current job openings. In addition, finding the right candidate with desired qualifications to fill their current job openings is an important task for the recruiters of any organization. Online Job Search Portals have certainly made job seeking convenient on both sides. Job Portal is the solution where recruiter as well as the job seeker meet aiming at fulfilling their individual requirement. They are the cheapest as well as the fastest source of communication reaching wide range of audience on just a single click irrespective of their geographical distance.
The web application “Job Search Portal” provides an easy and convenient search application for the job seekers to find their desired jobs and for the recruiters to find the right candidate. Job seekers from any background can search for the current job openings. Job seekers can register with the application and update their details and skill set. They can search for available jobs and apply to their desired positions. Android, being open source has already made its mark in the mobile application development. To make things handy, the user functionalities are developed as an Android application. Employer can register with the application and posts their current openings. They can view the Job applicants and can screen them according to the best fit. Users can provide a review about an organization and share their interview experience, which can be viewed by the Employers.
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Practical Cursive Script RecognitionCarroll, Johnny Glen, 1953- 08 1900 (has links)
This research focused on the off-line cursive script recognition application. The problem is very large and difficult and there is much room for improvement in every aspect of the problem. Many different aspects of this problem were explored in pursuit of solutions to create a more practical and usable off-line cursive script recognizer than is currently available.
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Investigation into the mechanics and feasibility of continuous counter-current extractionHeuvel, Remco Nicolaas Antonius Marian van den January 2008 (has links)
Continuous counter current extraction (CCCE) or dual flow counter current chromatography (DFCCC) is a promising technique where components can be separated continuously by two liquid phases that flow in opposite directions through a continuous length of coiled tubing. Specially designed end connectors and a coil planet centrifuge allow each respective phase to be pumped into each end of the tubing and the other phase to elute at each opposite end. In this thesis the feasibility and the mechanics of CCCE are investigated using stroboscopic photography on an experimental rig and a specially built pilot-scale CCCE centrifuge. The mechanics of the hydrodynamics in the coil was investigated systematically by comparing the measured volumes with photographic images of the process. This investigation revealed that the phases are not distributed evenly throughout the coil, which was previously assumed, but that there is a transition area where the phases switch from mainly upper phase at the head end of the tubing to mainly lower phase at the tail end. This means that the sample encounter three different phase distribution zones in the coil. At the head the upper phase is the dominant phase with a small volume of lower phase running through. At the tail the reverse situation is found and lower phase is dominant. The third zone is a short segment of the coil where there is a transition between the dominant phase conditions that exist at each end. The position of the transition zone and the volume of the other two zones are profoundly affected by the relative flow rates of the two phases. This work indicates that the volume distribution in the coil is affected most by the upper phase flow rate. The pilot-scale CCCE centrifuge was used to successfully separate industrially supplied samples. Crude reaction liquor was processed in both batch and continuous modes achieving the separation of the multi-component mixture into two groups. Changing the flow rate combinations changed the location of elution of some of the components in the mixture. Separation efficiency was maintained even when sample loading was increased. The separations were shown to be predictable with the dual flow theoretical model.
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Analyse des disparités provinciales dans l'application des lois sur les drogues au Canada de 1977 à 2000Dion, Guy Ati January 2003 (has links)
Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal.
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